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Oysters

Crassostrea virginica

Also known as Eastern oyster, Rock oyster, Huitres

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Filter-feeding bivalve molluscs, farmed and wild-harvested, whose flavour tracks the water they grew in closely enough that regions are named on menus. They are the densest common dietary source of zinc.

Immune HealthWomen's HealthMen's Health

Potential health benefits

Best supported: Limited

Ordered by how well the human research supports them — strongest first. A rating describes the state of the evidence, not how impressive the food is. How we rate evidence.

Immune function

Immune Health
Limited evidence

Contains compounds associated with normal immune function, principally zinc. The human evidence concerns zinc status and supplementation rather than oysters as a food, and applies mainly to people whose intake is inadequate.

Limited evidence. Early human work, or mostly lab and animal research.

2 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Iron status

Women's Health
Insufficient evidence

Has been studied as a source of well-absorbed iron. Oysters carry more iron than most seafood, but trials measuring iron status after eating them are scarce.

Insufficient evidence. Not enough human research to say anything useful yet.

No source is attached to this association yet, so it is rated insufficient by default. It is listed because people commonly ask about it — not because there is evidence for it.

Prostate health

Men's Health
Insufficient evidence

Evidence is limited for oysters affecting male reproductive or prostate outcomes. The reputation rests on their zinc content and long-standing folklore; no controlled human trial has tested oysters for these endpoints.

Insufficient evidence. Not enough human research to say anything useful yet.

1 source

Deep research mode adds each paper’s own conclusion and stated limitations.

Ask about Oysters

Ask about Oysters

Answers are written only from the entries on this page — the same nutrients, compounds, claims and citations you can read above. Nothing is added from outside the database, and every answer lists what it was built from.

AI explanations are not switched on for this site, so there is nothing to ask here. Everything above is read straight from the database and does not need them.

Key nutrients

Nutrient content per 100 grams
NutrientAmount% DV
Macronutrients
Calories51 kcal3%
Protein5.71 g11%
Total fat1.71 g2%
Carbohydrate2.72 g1%
Fibre0 g0%
Total sugars0.62 g—
Water89 g—
Fats
Saturated fat0.474 g2%
Monounsaturated fat0.253 g—
Polyunsaturated fat0.528 g—
Cholesterol40 mg13%
EPA (omega-3)0.177 g—
DHA (omega-3)0.136 g—
DPA (omega-3)0.01 g—
Linoleic acid (omega-6)0.041 g—
Vitamins
Vitamin A13 µg1%
Vitamin C0 mg0%
Vitamin D0 µg0%
Vitamin E0.85 mg6%
Vitamin K1 µg1%
Thiamin (B1)0.018 mg2%
Riboflavin (B2)0.09 mg7%
Niacin (B3)0.925 mg6%
Pantothenic acid (B5)0.223 mg4%
Vitamin B60.031 mg2%
Folate7 µg2%
Vitamin B128.75 µg365%
Choline65 mg12%
Minerals
Calcium59 mg5%
Iron4.61 mg26%
Magnesium18 mg4%
Phosphorus97 mg8%
Potassium156 mg3%
Sodium85 mg4%
Zinc39.3 mg357%
Copper2.86 mg318%
Manganese0.296 mg13%
Selenium19.7 µg36%
Other measured compounds
Beta-carotene0 µg—
Alpha-carotene0 µg—
Lycopene0 µg—
Lutein + zeaxanthin0 µg—
Caffeine0 mg—
Ash0.82 g—

Nutrient values are per 100 g of the USDA reference entry named on this page and vary with variety, growing conditions, storage and preparation.

Source record: Mollusks, oyster, eastern, wild, raw (USDA FoodData Central, FDC ID 171978).

% DV uses the FDA Daily Values for adults and children aged 4 and over. A dash means no Daily Value has been established for that nutrient.

Bioactive compounds

Compounds present in meaningful amounts. Presence is banded rather than quantified, because whole-food levels vary enormously with variety, growing conditions, storage and preparation.

How preparation changes things

Only effects with real support are listed. If a preparation method is missing, it is because nothing dependable is documented — not because it makes no difference.

  • cookedReduces Vibrio and norovirus

    Thorough cooking is the only reliable step that inactivates Vibrio and viral pathogens in oysters. Post-harvest processing such as high-pressure treatment reduces but does not eliminate risk.

Things to know

Allergies, interactions and intake concerns. Every food gets this section — a reference where everything is uniformly good is not a reference.

  • Worth knowing

    Raw oysters and Vibrio vulnificus

    Raw oysters are the leading food vehicle for Vibrio vulnificus, which causes severe and sometimes fatal infection in people with liver disease, haemochromatosis, diabetes or immunosuppression. Hot sauce, lemon and alcohol do not inactivate it; only cooking does.

  • Allergy

    Mollusc shellfish allergy

    Molluscs are a separately regulated allergen from crustaceans in the EU and elsewhere. Some people react to both, others to only one group.

  • Too much

    Zinc and copper balance

    A few oysters can exceed the tolerable upper intake level for zinc several times over. Sustained very high zinc intake interferes with copper absorption and can cause copper deficiency.

  • Too much

    Purines and gout

    Shellfish including oysters are moderately high in purines and are commonly limited in gout dietary advice.

  • Worth knowing

    Norovirus and biotoxins

    As filter feeders, oysters concentrate norovirus from contaminated water and can accumulate algal biotoxins during blooms, which is why harvest areas are closed and monitored.